1. Field of the Invention
The present invention pertains to security devices. More specifically, the present invention pertains to a security device for preventing opening of a hinged door.
2. Description of the Prior Art
Most doors, particularly those which provide ingress and egress to a house or building, are usually provided with some type of door lock to prevent unauthorized opening of the door. Most of such locks are opened or locked with a key or some other mechanism which is operable from the exterior of the door. While many of these locks are very secure, others may be easily overcome by an intruder. In fact, expert intruders are capable of overcoming most any door lock which is accessible from the exterior of the door.
To provide additional door security, a number of security devices have been developed as supplemental or secondary locks to thwart entry of an intruder even if the primary door lock has been overcome. Most of these secondary or supplemental security devices are operable only from the interior of the space in a house or building for which the door serves as entry. Thus, the security device cannot be tampered with by an intruder on the exterior of the door.
Many of these secondary security locks or devices take the form of a latch or sliding bolt which is manipulated from the interior side of the door by rotating a latch knob or sliding a bolt so that the latch or bolt engages a corresponding latch or bolt receiving slot to prevent the door from opening. Examples of such designs are shown in U.S. Pat. Nos. 1,043,231; 2,469,610; 3,809,415; and 4,673,202. While these designs may be effective in certain situations, some may be overcome by an intruder placing great forces on the edge of the door.
There are a number of other security devices in which a sliding element is provided which is slidingly retractable to allow opening of the door but which slides into a position engaging the edge of the door to prevent opening thereof. Examples of these devices are shown in U.S. Pat. Nos. 3,537,739 and 4,227,724. Most of these security devices are relatively weak and do not provide security against an intruder using some means of applying a great force to the edge of the door.
In more recent years, security devices have been provided of generally two components. One of the components is some type of member which is securely fastened to the door jamb so that it cannot be removed unless the door is opened. A corresponding plate or bar element is provided which engages an extension of the door jamb element to engage the free edge of the door upon attempted opening thereof preventing its opening. Examples of these type of security devices are shown in U.S. Pat. Nos. 3,316,005; 4,958,868; and 5,098,142. Such designs are relatively simple to install and operate and are fairly effective. However, with increasing criminal activity, improvements in these designs are continuously sought.